A laser scanning system for scanning a laser beam of a hair cutting device comprises a moving optical device like e.g. a vibrating array of optical means to direct a number of focal spots in a harmonic motion over the skin of an individual. Said vibrating motion of the array ensures that every point covered by a detection device has been examined for the presence of hairs and/or has, potentially, been shaved by guiding high power optical pulses to each detected hair.
Document WO 2007/013008 A1 describes a hair-removing system comprising a hair-detection device and a hair-removing device that is operatively coupled to the hair-detection device as well as an image sensor to detect an image of a part of the skin to be treated, wherein the image sensor comprises a moving array of lenses.
Because of the vibratory motion of the optical means, in most designs a tracking mechanism is employed to ensure a continuous overlap or allignment of the laser beam with the movable optical device. This tracking mechanism could consist e.g. of an electro-optical or acousto-optical deflector, a vibrating tracking mirror or tracking prism, a liquid crystal beam deflector, etc. The tracking mechanism needs to be accurately synchronized with respect to the phase, amplitude, and actual resonance frequency of the movable optical device and its associated mechanics and actuators. Furthermore, the tracking mechanism needs to be fast enough to track the motion of the movable optical device and be able to handle the detection laser light and preferably also the high power cutting laser light and be generally compatible with the overall requirements for laser shaving (i.e. low cost, low voltage, small in size, low power consumption, etc.). This set of requirements is difficult to meet using the solutions mentioned above. Furthermore, the solutions should also work in many ambient conditions (temperature, pressure, moisture) and be reasonably shock resistant and very reliable.